Vaccines incubated in egg for allergic children
It has been subject of debate whether children allergic to egg proteins should be vaccinated with vaccine incubated in eggs that could contain traces of it.
There are three types of vaccines that are grown or cultured in egg derivatives: MMR, influenza and yellow fever vaccines. The rabies vaccine is grown in human diploid cells and does not contain traces of egg protein.
This vaccine is cultured from fibroblasts of chick embryos. It does not contain sufficient egg protein to produce an allergic reaction. Therefore all children with egg protein allergy should receive their MMR vaccine normally.
Only children who have had a previous adverse reaction with such vaccination should be vaccinated by an allergist.
Generally these reactions are caused by the components of gelatin or neomycin contained in these vaccines.
Moreover, the recommended time for the administration of the MMR vaccination is at 12 months, when egg has still not become part of the child’s diet.
The influenza vaccine is known as the flu vaccine. Administration of the first dose of influenza vaccine is recommended at 6 months in children with asthma or who live with patients at risk of respiratory diseases. Furthermore, a third of children with egg allergy have asthma.
This vaccine is incubated in chick embryos inoculated with different influenza viruses, and therefore contains different traces of ovalbumin.
The amount of egg protein in the vaccine is expressed by the amount of ovalbumin content per dose. Children who have egg allergy, but do not have severe anaphylaxis, can tolerate the amount of up to 1 µg / dose of ovalbumin, although for safety vaccines should be administered at a center where there is knowledge of how to treat a reaction that could occur.
For higher than 1 µg / dose concentrations of ovalbumin, a dose of 1/10 of the total should be administered firstly and after 30 minutes, if there is no reaction, the rest (9/10). You can also apply the same divided doses in patients with anaphylactic reactions to egg, but with vaccines with low amount of ovalbumin (less than 1 µg / dose) provided it is done by an allergist at a center with means for controlling the reactions.
If a second dose is necessary in a month’s time, and no previous adverse reaction has occurred when doses are divided, it may be administered in a single dose.
It would be contraindicated the administration of influenza vaccine in patients with egg allergy who have had a previous severe anaphylactic reaction following administration of influenza vaccine.
Yellow fever vaccine
This contains live attenuated viruses, is cultured in chick embryos and the amount of ovalbumin it may contain is unknown.
Should you require vaccination in a patient allergic to eggs, you should perform a skin test 1/100 with this vaccine and if it is positive and vaccination is essential, desensitization for this vaccine should be performed at hospital.